A security firm has uncovered a porn-themed attack on YouTube users, which is using links in video descriptions to forward watchers to an SMS gateway to continue viewing the clip -- with the rather obvious result being an enormous mobile phone bill.

The porn playlists are targeting Russian users, which, according to Malwarebytes, could be why Google's not yet detected the scam. Malwarebytes has discovered entire playlists packed with hardcore porn (tough job), which have been uploaded via a mix of new and dormant older (presumably hacked) accounts.

Some clips come with links that take users to an age restriction gateway, which asks users to confirm their age via SMS. Hopefully massive and very loud mental alarm bells would start ringing when someone's confronted by this, as it ends up pinging premium text messages to users instead.

Other porn clips found on YouTube link viewers to Russian sites associated with the distribution of malware. Lesson being: Don't click the links.